1. Field of the Invention
This invention relates to a cassette loading device for use, for example, in a video tape player for recording and reproducing video signals and the like using a magnetic tape.
2. Related Art
Recently, video tape players have been desired to be compact and lightweight, and therefore a cassette loading device which is one constituent element of the video tape player has also been desired to be compact and lightweight.
A conventional cassette loading device will now be described.
FIG. 16 is a perspective view of the conventional cassette loading device in a cassette loading/unloading position, FIG. 17 is a side-elevational view showing a tape guide portion in a cassette-down position of the conventional cassette loading device, FIG. 18 is an enlarged top plan view showing the positional relation between an opener of the cassette loading device and a cassette, and FIGS. 19 and 20 are a side-elevational view and a cross-sectional view of the cassette loading device in the cassette-down position, respectively. In FIG. 16, the cassette 101 has a lid 101a,and a cassette holder 102 releasably holds the cassette 101. Each of a first arm 103 and a second arm 104 is supported for pivotal movement at one end thereof and for sliding movement at the other end thereof, and the two arms 103 and 104 are pivotally engaged with each other generally at their central portions. A stand 105 has the axis of pivotal movement of the first arm 103, and a sliding groove for the second arm 104. A spring 106 is engaged with the first and second arms 103 and 104, and urges the cassette holder 102 from the cassette-down position (FIGS. 17 and 19) toward the cassette attachment/detachment position (FIG. 16). Biasing springs 107 are fixedly secured at their one ends to the cassette holder 102. An opener 108 is pivotally connected at one end 108a to the cassette holder 102, and is engaged with a slide pin 103a of the arm 103. A guide 109 serves to prevent a magnetic tape 100 from running on a cylinder 111 when the magnetic tape 100 is slack, thereby preventing the magnetic tape 100 from being damaged. An outer shell 110 pivotally supports the guide 109.
The operation of the conventional cassette loading device of the above construction will now be described. First, in the condition shown in FIG. 16, when the cassette 101 is inserted into the cassette holder 102 in a direction of arrow A, the distal end of the opener 108 is disposed between the cassette 101 and the lid 101a as shown in FIG. 18. When the cassette holder 102 is manually moved toward the cassette-down position (FIGS. 17 and 19), the slide pin 103a of the arm 103 moves along a slide groove in the cassette holder 102, and the engagement portion of the opener 108 is pivotally moved about its end 108a in a direction of arrow B in response to the movement of the slide pin 103a,thereby opening the lid 101a. Upon further movement of the cassette holder 102, if the magnetic tape 100 is slackened, the magnetic tape 100 moves toward the cassette-down position (FIG. 17) along the guide 109 without interfering with the cylinder 111. In the cassette-down position shown in FIG. 20, the cassette holder 102 is locked at a predetermined position of the device body by a lock mechanism (not shown), and the cassette 101 is engaged with positioning pins 112 on the device body, and is urged by the biasing springs 107 in the direction of arrow B, so that the cassette 101 is loaded and fixed at a predetermined position. At this time, the guide 109 is engaged with the cassette lid 101a,and is pivotally moved about a pivot axis 109a as shown in FIG. 17 to be disposed between the cassette lid 101a and the cylinder 111. Then, when the lock mechanism is released, the first and second arms 103 and 104 are pivotally moved by the biasing force of the spring 106, so that the cassette holder 102 is returned to the position shown in FIG. 16 where the cassette 101 can be attached to and detached from the cassette holder 102. At this time, the guide 109 is released from the bias of the cassette lid 101aand is returned to the initial position, and then the lid 101a is closed.
As regards a first problem of the above conventional construction, since the guide 109 is mounted on the outer shell 110, it is difficult to precisely position the guide 109 relative to the cylinder 111, and a gap between the guide 109 and the cylinder 111 must be secured, which results in a problem that the device can not be of a compact construction. And besides, the cassette lid 101a must be opened at an early timing, and a sufficient design margin of the opener 108 can not be obtained.
As regards to a second problem, the opener 108 must be provided on the outer side of the cassette holder 102, and therefore the number of the component parts arranged in the longitudinal direction of the cassette is increased, which results in a problem that the device can not be of a compact construction. Moreover, there has been encountered a problem that when the cassette holder 102 is moved down during the insertion of the cassette 101, the opener 108 fails to be engaged with the lid 101a. Further, if it is intended to solve this problem, a mechanism separate from the opener 108 must be provided, which results in a problem that the number of the component parts is increased, so that the device becomes heavy.
As regards a third problem, for example, in the case of a video tape player, the projected area ratio of the cassette loading device to the whole of the video tape player is made large when the overall construction is to become compact, and in this case it is desired to provide operating switches, including a recording switch, a playback switch and a stop switch, on the top surface of the cassette holder 102; however, since the cassette holder 102 is moved generally linearly, it is difficult to mount the wiring of such switches.
As regards to a fourth problem, when the cassette 101 is loaded, the reaction force of the biasing springs 107 acts on the cassette holder 102. When the cassette 101 is unloaded, the reaction force of the biasing springs 107 does not act on the cassette holder 102. Therefore, there has been encountered a problem that the position of the cassette holder 102 varies depending on whether or not the cassette 101 exists. Moreover, the pair of biasing springs 107 are needed for fixing the cassette 101 to the device body in the cassette-down position shown in FIG. 17, and besides a shaft 113 for aligning the right and left movements of the cassette holder 102 with each other is required, which results in a problem that the number of the component parts is increased. This is disadvantageous in making the device compact and lightweight. Further, if it is intended to overcome the above problem, a mechanism separate from the cassette holder is needed, and for example, in the case of the video tape player (final product), the number of the component parts is increased, and the video tape players becomes larger and heavier.